Focal plane shutter



Oct. 27, 1936. w. A. RIDDELL v 2,058,506v

FOCAL PLANE SHUTTER Filed June 11, 1935 2 Sheets-Sheet 1 FEB. FHEZ, FHEUEO a W FE-QM" IN VENTOR.

William A .Rz'ddell flaumxakix whim ATTORNEYS Oct. 27', 1936. R DELL 2,058,506

FOCAL PLANE SHUTTER Filed June 11, 1935 2 Sheets- Sheet 2 49 40 Z4 0 FEB 7a 39 36 29 49 27 2 8 I 51 35 16 v 12 45 46 23 I Q I h 44 FUEJS. Z2 17 4.94

INVENTOR.

William A .Riddell BY mfzm ATTORNEYS Patented Oct. 27, 1936 UNlTED STATES FOCAL PLANE SHUTTER William A. Riddell, Rochester, N. Y., assignor, by

mesne assignments, to Eastman Kodak Company, Jersey City, NHL, a. corporation of New Jersey Application June 11, 1935, Serial No. 26,025

14 Claims. (Cl. 95-.-57)

Ihis invention relates to focal plane shutters,

and an object of the invention is to produce a shutter mechanism in which two curtains can be readily adjusted relative to each other to vary the exposure aperture. Another object is to provide a simple form of clutch between rollers carrying the two curtains. Another object is to provide a means for retaining the exposure aperture constant during exposure and other objects will appear from the following specifications the novel features being particularly pointed out in the claims at the end thereof.

In small sized cameras, and particularly in small sized cameras intended primarily for use with roll film, there is comparatively little space to mount the so-oalled focal plane or curtain shutter. I have provided an extremely simple type'of focal plane shutter which may have a wide variation in shutter speeds due to the ad- 20 justable width of theexposure aperture, and I have also provided a shutter which can be contained in a relatively small space.

Coming now to the drawings wherein like reference characters denote like parts throughout:

Fig. 1 is a side elevation of a camera having a shutter embodying this invention;

Fig. 2 is a .vertical section thereof;

Fig. 3 is an elevation of the shutter curtains separated from the enclosing parts of the mechanism and in somewhat diagrammatic form;

Fig. 4 is a front view of the camera body and shutter, the bed and lens and associated parts being removed; 4

Fig. 5 is an enlarged fragmentary view of a part of Fig. 4;

Fig. 6 is a side elevation, enlarged, of a part of Fig. 4;

Fig. 7 is a sectional elevation of the upper portion of the shutter mechanism;

Fig. 8 is a section on line 8-8 of Fig. '7;

Fig.9 is a partial side elevation from the right end of Fig. '7; I

Fig. 10 is a vertical section of the central portion of the shutter at the left side of Fig. 4; and

Figs. 11, 12 and 13 are sections on lines lll l, I2-I2 and i3-l3 respectively of Fig. 10.

Broadly speaking, my shutter consists'of two.

separate curtains, each .one of which may be wound upon a spring-driven roller at one end, and the opposite ends of each of the curtains are attached to coaxially arrange spools which are separate save'for a clutch member. This clutch member includes friction surfaces tending to cause the spools carrying the two curtains to 55 move together in both directions. The clutch one direction.

insure that the width of the slot between the two curtain members will remain the same width throughoutall of the exposure. It is also necessary to have the two curtains move independently of each other at the beginning and at the end of each exp0surein the one case for closing the slot to wind the shutter across the exposure area, and in the other case to permit the slot to open up before the exposure is made.

In other words, my shutter is what is known as a self-capping shutter, that is to say, the opening in the shutter is completely closed during the shutter winding or setting operation.

A shutter constructed in accordance with a preferred embodiment of the present invention is shown mounted in a cameraof the usual folding type, wherein a camera body I, having film spool chambers 2 and 3 for spools 4 and 5 respectively, has a back or closure 6 and a bed I. A lens board 8 carries the lens mount 9 and the front end of bellows Hi, the rear of the latter'having suitable light-tight connection with the camera body I. An external winding knob to may be provided for turning the spool 4 as is usual in roll film cameras. The foregoing parts are not illustrated in full detail, as they maybe of any suitable construction and are merely indicated to such extent as will make clear their relation to the shutter.

The shutter mechanism is mounted on and within a housing I2, which is comparatively deep. Flanges l3 at the top and bottom of the housing l2 lie in suitable recesses in the camera body I and screws or pins it serve" to secure the housing in place, with its rear wall l5 close to and parallel with the camera back 6. A groove or recess I6 is provided in the rear wall l5 to serve as a guide for the film F.

Near the top of the housing I2 is a shaft l'l extending through the side walls t8 and IQ of the housing (Fig. 7), and freely revolvable in trunnions 20. A knob 2|, a washer 23 and a gear 24, are secured on a sleeve 25 in a suitable manner, as by riveting or staking the 1 ends 26 of the sleeve, and these parts as a unit are free to turn on the shaft l| without rotating the latter or being rotated by it. The sleeve 25 is retained on the shaft I1 by a stud 22, the position of the sleeve longitudinally of the shaft being established by a flange 21.

Near the knob end of the shaft I1 is a drum 28 and at the other end of the shaft is a similar drum 28, both of these drums being secured to the shaft H to. turn with it, as by pins 30. Between the drums 28 and 29 is a spool 3|, free to rotate on the shaft l1, and having flanged ends. The flange nearest the drum 28 carries a gear 32, while the flange toward the drum 29 has a circle of ratchet teeth 33 on its end face.

Within the spool 3| is a collar 34 pinned, to the shaft H at 35, and between this collar and the drum 29 is a metal disc 38 between two washers 31 of fiber or similar friction-surfaced material. A metal washer 38, with lugs 39 that engage slots 48 in the collar 34 is between the latter and one of the discs 31. In assembling the foregoing parts, they are pressed together and the pins 30 and 35 are then set so that there will be considerable frictional engagement between the disc 38, washers 31 and 38, collar 34 and drum 28. Anti-friction bearings 3| 0. may be interposed between the spool 3| and the drum 28 to permit free relative movement of these members. The disc 38 has two or more tongues 36a that engage the ratchet teeth 33 when the assembly is completed as above mentioned, so that the disc 38 the drums 28 and 23, and the shaft will movewith the spool 3| when the spool is rotated in the direction of the upper arrow in Fig. 1. The results of such movement will be described hereafter.

On the end of shaft ll opposite knob 2| is fixed a disc 4| having a radially-projecting lug 42 (Fig. 9). Between this disc and a plain washer 43 (Fig; 7) is a disc 44 having a radial lug 45 and a laterally bent lug 46. The disc 44 is in light frictional engagement with the washer 43 and the disc 4|, so that it will be carried around with the disc 4| when the shaft I1 is first rotated, but will be stopped when the lug 45 strikes one end of an adjustable stop 41. This stop may be mounted on the shutter housing |2 by means of screws 41a extending through slots in the stop piece. The above arrangement permits the shaft IT to be rotated a predetermined amount, being in the present instance approximately one and one quarter revolutions.

At the knob end of shaft I1 is a group of discs arranged to limit in a similar manner the turns,

that the knob 2| may make, for purposes which will presently appear. Two discs, 48 and 49 are loose on the sleeve 25, and the third, 23, is fast on the sleeve as hereinbefore mentioned. As the knob 2| is turned as indicated by the arrow in Fig. 8, a radial lug 23a on the disc 23 picks up the disc 48 after the shaft H has made approximately one revolution, by contacting a lateral lug 48a thereon, and a radial lug 48b on said disc 48, after both 23 and 48 have made another revolution, picks up disc 49 by contacting its lateral lug 48b. The lug 48b strikes the upper front edge 58 of a subframe |2a that is mounted at one side of the housing l2, thus preveniing fur ther rotation of the knob 2|, gear 24, and sleeve 25. The arrangement and relative positions of the various stop lugs may be modified as required, the knob 2| in the present instance being permitted to make approximately'il revolutions.

The curtain members which constitute ooz trollable exposure elements are arranged to move vertically in a plane close to the film F. The front curtain member 5| of the shutter is wound on the spool 3| and on a spring-actuated curtain roll 52 near the bottom of the housing 2. This front curtain has an aperture 53 that corresponds to an exposure aperture A in the rear wall l5 of the housing i2.

The rear curtain 54 is wound on a springactuated roll 55 below and in front of the roll 52, and the upper portion of this curtain terminates in tabs 58 which are attached to and wound on the drums 28 and 29 previously described.

As in many shutters of the focal plane type, the two curtains are arranged to have independent movement when the shutter is being set, whereby the height or area of the exposure aperture is controllable, and to have coincident movement when released, to cause this aperture or slot to move uniformly past the frame aperture A. The variable-height slot is obtained by moving or winding-up the curtain 5| farther than the curtain 54, whereby the upper edge 53a of the aperture 53 is carried past the upper edge 54a of the curtain 54 to a distance that may be from a fraction of an inch up to a distance equal to the full height of the aperture 53.

The gear 24 meshes with another 51, on an idler shaft 58 (Fig. 7) which in turn carries a gear 59 that meshes with the gear 32 forming part of the spool'3l. The latter therefore must rotate when the knob 2 I is turned, whether shaft moves or not. However, the shaft being in frictional engagement with spool 3|, as previously described moves with it until stopped by the lug 46 on the washer 44, so that under the above condition, the curtains 5| and 54 are simultaneously drawn from their rolls 52 and 55 and are par tially wound up on the spool 3| and on the drums 2B and 29 respectively. However, the drums 28 and 29 and therefore curtain 54, are stopped by the stoppage of shaft l1. If the knob 2| is further turned the spool 3| will continue to wind up the curtain 5| and draw the edge 53a past the edge 54a of the rear curtain 54 to provide an exposure slot on the return movement of both ourtains.

The distance the edge 54a moves before the drums 28 and 29 are stopped by the discs 44, 46,

etc. is sufficient to carry said edge above the top of frame A, so that there will be no exposure slot or gap within the exposure area. The maximum amount of winding or overrun of the edge 531: after the drums 28 and 29 have been stopped is determined by the lug 481) 'as previouslydescribed, such maximum preferably being equal to the height of frame A. Means, about to be described, are provided for limiting the overrun of edge 53a to a plurality of lesser distances to control and determine the height of the exposure slot.

Through a gear 68 on an idler shaft 8|, a pinion 82 drives a gear 53 on a shouldered stud 84 that projects through the side wall I! of casing l2, (Fig. 11). A ratchet 85-is in effect,part 'of gear 83, by reason of a stop pin 88 projecting through its latter, so that the ratchet and gear move together. The stop pin 85 projects into an annular recess 61 in a timing knob ,88. The recess 61 is interrupted by a bridge 89 that may be engaged by the pin 88 in certain positions of the knob 68, selective positions of the knob being determined by an index point 18, adapted to engage any one of a series of notches 1| in the subframe plate |2a. This index point drops readily into the selected notch under pressure of a spring 12 that reacts against a retaining screw 13 to press the knob 68 toward the housing. A stop 14 (Fig. 13) in the plate I 2a also limits the extreme movement of the pin 85.

It will be apparent tha -f the index point HI is set into the notch farthest to the left in Fig. 13,

the bridge 59 in the timing knob 68 will permit the stop pin 65 to move a distance in the direction indicated in Fig. 12 that will be considerably .action 'of the discs 48 and 48 etc;

A pawl 15, having a lug 15a projecting through the wall I8, is held in contact with the ratchet -65 by a spring 18, to retain the entire mechanism in the set position until the lug 15a is moved in the direction of the arrow in Fig. 13, whereupon the spring-actuated rolls 52 and 55 are free to act in unison and pull down the curtains 5| and 54, and carrying the exposure aperture from top to bottom of the frame A to make the exposure. r

After release, the curtain 54 comes to rest first, at a point determined by the contact of lug 45 with the stop 41, said lug moving atthis time in a direction opposite to the arrow in Fig. 9. The roll 52, still being turned by its spring 82 to wind the curtain 5| on itself, causes the spool 3| to overcome the frictional grip of the washers 31 and 38, and the ratchet 33 then overruns the tongues 36a on the disc 36, until the roll 52 has carried the curtain 5| a distance sufficient to reestablish the relative positions of the two curtains indicated in Fig. 3, although the portions which are shown as overlapping actually will be on the rolls 52 and 55 respectively. Free-turning sleeves 52a on the roll 52 facilitate the relative movement of the two curtains and obviate the necessity of an idler roll for the curtain 54.

While the springs which wind up rolls 52 and 55 are not illustrated in detail, being of well known curtain-roll construction, means are embodied in this invention whereby the tension of these springs may be adjusted. To this end, pintles an and. 8| are connected respectively, to the springs 82 and 83 in rolls 52 and 55, and extend through the wall IQ of the housing l2 and carry pinions a and file which are fast to said pintles (Fig. 6). These latter turn together whenever the pintle of either is rotated, by reason of their connection through an idler pinion 84. Screws and 86 pass through a clamp plate 81, and by setting up these screws the plate 81 holds the pinions 80a and 8la against rotation, preventing springs 82 and 83 from unwinding. By loosening the two screws 85 and 86, the pintles 80 and 8| may be turned by a suitable tool, the

rotation or winding of either one correspondingly moving the other, so that the tension of each spring is increased to the same extent. The screws are then tightened and the plate 81 then holds the three pinions and therefore the pintles,

against rotation.

It should be noted that in the construction of this shutter one element of the shutter curtains is moved to set" position positively, through the gear connections actuated from the manuallyoperated windup knob, whereas the second curtain element is moved to set position through frictional engagement with the first element, until arrested by a stop. This frictional engagement is also effective when the shutter is released, until one element is stopped at the end of its return movement, the other element then overcoming this frictional engagement and being carried to its stop position by actuating means of sufllcient power.

While I have illustrated and described a preferred embodiment of my invention, it will be understood that the invention is not confined to the single type illustrated and described but only by the appended claims.

I claim:

1. In a curtain shutter, the combination with two.curta.ins, each defining a part of a variable exposure aperture, of three coaxially arranged drums for supporting portions of the two cur-,

tains, a'friction clutchbetween two of the drums supporting portions of the two curtains, and a pawl and ratchet for causing the clutch to always drive in turning in one direction.

2. In a curtain shutter, the combination with two curtains, each defininga part of a variable exposure aperture, of a shaft, a plurality of drums carried by said shaft adapted to support portions of the two curtains, the drum carried by said shaft for supporting a portion of one curtain being free to turnon said shaft, the other curtain drum supporting rollers being keyed to said shaft, means tending to turn the keyed drum from the drum free to turn thereon.

3. Ina curtain shutter, the combination with two curtains, each defining a part of avariable exposure aperture, of a shaft, a plurality of drums carried by said shaft adapted to support portions of the two curtains, the drum carried by said shaft for supporting a portion of one ourtain being free to turn on said shaft, the other curtain drum supporting rollers being keyed to saidshaft, means including a pawl and ratchet for turning the freedrum from the keyed drum in one direction.

4. In a curtain shutter, the combination with two curtains, each defining a part of a variable exposure aperture, of a shaft, a plurality of drums carried by said shaft adapted to support portions of the two curtains, the drum carried by said shaft for supporting a portion of one ourtain being free to turn on said shaft, the other curtain drum supporting rollers being keyed to said shaft means tending to turn the keyed drum from the drum free to turn on the shaft and means for positively connecting the keyed and free drums for turning the former in one direction.

5. In a curtain shutter, the combination with two curtains, each defining a part of a variable exposure aperture, a spring driven roller for one end of each curtain, a plurality of coaxially arranged drums for supporting the opposite ends of each curtain, a shaft supporting said coaxially arranged drums revolvably supporting one drum and keyed to another drum, means for limiting the number of revolutions the shaft and keyed drum can make, a winding knob, connections between the winding knob and revolvably mounted drum for manually turning said drum, and a slip connection between said drum and said keyed drum tending to turn the keyed drum, from the revolvably mounted drum.

6. In a curtain shutter, the combination with two curtains, each defining a 'part of a variable exposure aperture, a spring driven roller for one end of each curtain, coaxially arranged drums for supporting the opposite ends of each curtain, a'shaft supporting said coaxially arranged drums, revolvably supporting one drum and keyed to another drum, a winding knob, gearing connecting the winding knob and the revolvably supported shaft, an adjustable stop limiting the winding movement of the knob and drum, and slip connections between the revolvably mounted drum and the keyed drum tending to turn the latter with the former.

'7. In a curtain shutter, the combination with two curtains, each defining a part of a variable exposure aperture, a spring driven roller for one end of each curtain, coaxially arranged drums for supporting the opposite ends of each curtain, a shaft supporting said coaxially arranged drums, revolvably supporting one drum and keyed to another drum, a winding knob, gearing connecting the winding knob and the revolvably supported shaft, an adjustable stop limiting the winding movement of the knob and drum, and slip connections between the revolvably mounted drum and the keyed drum tending to turn the latter with the former, and supplementary means for turning the drums together in one direction.

8. In a curtain shutter, the combination with two curtains, each defining a part of a variable exposure aperture, a spring driven roller for one end of each curtain, coaxially arranged drums for supporting the opposite ends of each curtain, a shaft supporting said coaxially arranged drums, revolvably supporting one drum and keyed to another drum, a winding knob, gearing connecting the winding knob and the revolvably supported shaft, an adjustable stop limiting the winding movement of the knob and drum, and slip connections between the revolvably mounted drum and the keyed drum tending to turn the latter with the former, and supplementary means for turning the drums together in one direction, including a pawl member, said pawl member also forming a part of said slip connection.

9. In a curtain shutter, the combination with two curtains, each defining a part of a variable exposure aperture, a spring driven roller for one end of each curtain, coaxially arranged drums for supporting the opposite ends of each curtain, a shaft supporting said coaxially arranged drums, revolvably supporting one drum and keyed to another drum, a winding knob, gearing connecting the winding knob and the revolvablysupported shaft, an adjustable stop limiting the winding movement of the knob and drum, and slip connections between the revolvably mounted drum and the keyed drum tending to turn the latter with the former, said slip connection including friction surfaces and a spring washer carrying a pawl, a ratchet carried by the revolvably mounted drum for said pawl to engage whereby the two drums may be driven through said pawl and ratchet through at least a portion of their relative movements.

10. In a curtain shutter, the combination with two curtains, each defining a part of a'variable exposure aperture, a spring driven roller for one end of each curtain, coaxially arranged drums for supporting the opposite ends of each curtain, a shaft supporting said coaxially arranged drums, revolvably supporting one drum and keyed to another drum, a winding knob, gearing connecttng the winding knob and the revolvably supported shaft, anadjustable stop limiting the winding movement of the knob and drum, and slip connections between the revolvably mounted drum and the keyed drum tending to turn the latter with the former, said slip connection including a pawl, a ratchet for the pawl to engage said pawl and ratchet supplementing said slip connection in driving the drums together through a portion of their relative movement in one direction.

11. In a curtain shutter, the combination with two curtains, each defining a part of a variable exposure aperture, a spring driven roller for one end of each curtain, coaxially arranged drums for supporting the opposite ends of each curtain, a winding knob for "winding portions of each shutter on the coaxially arranged drums, a trigger for releasing the shutter permitting the spring driven rollers to wind the curtains thereon, means including a slip clutch for causing the coaxially arranged rollers to unwind together during at least a portion of their movement.

12. In a curtain shutter, the combination with two curtains, each defining a part of a variable exposure aperture, a spring driven roller for one end of each curtain, coaxially arranged drums for supporting the opposite ends of each curtain, a winding knob for winding portions of each shutter on the coaxially arranged drums, a trigger for releasing the shutter permitting the spring driven rollers to wind the curtains thereon, means including a slip clutch for causing the coaxially arranged rollers to unwind together during at least a portion of their movement, said slip clutch including a pawl member as a part of the slip clutch, and a ratchet member on one drum, whereby continued movement of one curtain relative to the other is facilitated.

13. In a curtain shutter, the combination with two curtains, each defining a part of a variable exposure aperture, a spring driven roller for one end of each curtain, coaxially arranged drums for supporting the opposite ends of each curtain, a winding knob for winding portions of each shutter on the coaxially arranged drums, a trigger for releasing the shutter permitting the spring driven rollers to wind the curtains thereon, means including a slip clutch for causing the coaxially arranged rollers to unwind together during at least a portion of their movement, said slip clutch including a pawl member as a part of the slip clutch, and a ratchet member on one drum, said slip clutch including a spring washer keyed to one drum, 9. spring pawl carried by said washer, and a ratchet carried by the other drum whereby the coaxially arranged drums may be positively connected through at least a portion of their movement as the curtains are rewound on the spring drums.

14. In a curtain shutter, the combination with two curtains, each defining a part of a variable exposure aperture, a clutch member, a spring driven roller for one end of each curtain, coaxially arranged drums for supporting the opposite ends of each curtain, the two curtains being independently rollable back and forth between the spring drums and the coaxially arranged drums save for the clutch member, said clutch member including interengaging frictional surfaces tending to drive the drums together, and adapted to positively unite the drums for at least a portion of their movement in one direction.

WILLIAM A. RIDDELL. 

